Fuel



Patented Mar. 1, 1932 UNITED STATES PATENT OFFICE LEO IB. KIMBALL, OF NAUGATUCK, CONNECTICUT, ASSIGNOR TO FUEL DEVELOPMENT CORPORATION, A CORPORATION OF DELAWARE FUEL No Drawing.

This invention relates to liquid hydrocarbons, commonly used as fuels in internal combustion engines of the explosive type, particularly in automobile engines and in similar engines for otherpower purposes.

' The object of my invention is to produce a liquid fuel which shall have suitable vaporization characteristics and can be used in ugh-compression engines of the above men- 1 tioned type and which will also reduce the tendency, during combustion, to produce preignition, detonation or knocking.

It has been appreciated by various investigators in the art of hydrocarbon fuels for engines of the explosive type that aniline when added to a commercial fuel such as gasoline With a blending agent such as butanol, is efficacious in reducing detonation but its'use in gasoline and similar fuels is accompanied by various disadvantages which it has been though to be practically impossible to eliminate.

One of these disadvantages is that when aniline is mixed with gasoline or similar hydrocarbon fuel, the aniline has crystallized out and becomes separated from thegasoline at temperatures in the Vicinity of 10 above zero Fahrenheit. Various attempts have been made to prevent this crystallization of the aniline at low temperatures and some have been more or less successful by using as an additional ingredient, some more expensive fluid or liquid so that the homogeneity of the fuel is increased even at quite reduced temperatures.

These considerations become of great importance when gasoline is usedin airplanes which often, even in summer, reach high altitudes where the temperature may fall to from 25 to 50 below zero, Fahrenheit. A large proportion of benzol is usually incorporated with gasoline when the fuel is to be used at such low temperatures, to produce the necessary anti-knock characteristics.

I am familiar with the results of research of prior experimenters and patentees along these lines, but am not aware that any of them have attained the results and perfec tion of liquid hydrocarbons as fuels for internal combustion engines that I have at-' Application filed January 31, 1931. Serial No. 512,747.

tained by the combination of ingredients described below.

I have attempted to attain two'more mportant objects in the researches which I have attained, is the retention of aniline. and alcohol together in solution in gasoline sothat the same are not affectedbythe presence of water which may thereafter become mixed with the gasoline owing to condensation and h of moist atmosphere or other sources of moisture. This latter result is brought about by thefact that a small quantity of ethyl alcohol so combines with the aniline and butanol that the latter ingredients are not affected by the subsequent addition of moisture, and the aniline is therefore prevented from being crystallized even at such low temperatures as minus 40 F. Another advantage in using ethyl alcohol for this purpose is that the alcohol itself aids in reducing the tendency to preignition or knocking.

Ordinarily it isdesirable to use from 1% to 3% of aniline with one-tenth of one per cent. to one per cent. of butanol in gasoline used for the motor fuel. The amount of ethyl alcohol to cause the aniline to remain in solution should range from two-tenths or three-tenths of one per cent. up to three per cent. or slightly more, depending upon the amount of aniline introduced and the lower points of temperature to which the fuel may be subjected.

It will, of course, be appreciated that the higher the compression during the compression stroke of an automobile engine, the larger the amount of aniline will be neces sary to eliminate the detonation or knock.

Further advantages resulting from the use of my improved mixtures as fuels for internal combustion engines, arise from the fact that the temperatures of combustion are reduced to a lower point than can be obtained by the more common and somewhat inferior fuels in general use.

7 It has been found" in the use of many commercial fuels in engines for aeroplanes that such fuels heat the cylinder walls, the piston and the valves to such an extent that they can only be driven for a short time without sub stantial loss of power and subsequent damage to the engine. The use of my improved fuel has been found to reduce the combustion temperatures very materially andto apoint where they are not detrimental to the working parts of an internal combustion engine. Often, the effects of detonation in an engine, when they exist, are indicated largely by high -cylinder head temperatures. It has been found that during the wide open throttle operations of aircraft engines, certain fuels cause a marked rise in cylinder head temperatures which results in considerable damage to the valves and valve seats andin some cases the blowing in of the piston'heads.

A new scale of anti-knock ratings, recently adopted by automotive engineers, is based on a comparison of any particular fuel with a mixture of iso-octane in normal heptane, the result being that a certain percentage if isooctane can be introduced into the heptane to produce the same amount of detonation under similer conditions as is produced by the fuel being compared therewith. In other words, the percentage of iso-octane used in a mixture with heptane, designates the antiknock rating. Since normal heptane is considerably worse from a knock standpoint, than any of our common, modern fuels, and since iso-octane is better than any known fuel, these are taken as the ultimate zero and 100% values. Thus, mixtures of the two can be made which will duplicate any of the present commonly used fuels. Present automobile gasoline ranges from a octane number for very poor grades, to 64 for an avera e grade. In aircraft work best results are 0 tamed with fuels having octane numbers approaching 100.

In the case of aniline mixtures as described in this application, much advantage results from the fact that a neutral oil is used which contains no metallic element and therefore it can be added in sufiicient quantities without 1n ury to the engine and without forming scaly deposits on the exhaust valves and other parts, such as may result from the use of fluldscontaining metallic elements. It is also practically non-poisonous and does not require special precautions to prevent serious injury to operatives. The mixtures may be used at high altitudes wherethe atmospheric temperatures dro to low points. Furthermore, it has been f bund that the use of aniline mixtures as stated in connection with the fuels of this invention, produces an antiknock value in the vicinity of 3.5 octane numbers for each percent of the aniline mixture added to the fuel and the octane number may be raised to 100 or more. Thus, it is apparent that the anti-knock value of a fuel may be definitely controlled and the heating action upon the parts of an internal combustion engine may be reduced to the desired point for best efliciency under any conditions which may apply to an aircraft or automobile 811 1118. 7.

some hydrocarbon fuels which work well at low temperatures of combustion will not work at high temperatures because of the heating effect produced, and on the other hand, fuels which work at high temperatures,

such as 1n aeroplane engines, will not work well at lower temperatures of combustion, such as in automobile engines. Fuels which are made in accordance with the invention described in this application can be made to work well at either high or low temperatures of combustion, according to the amount of aniline and other ingredients added. In other words, the addition. of aniline, together with the other ingredients stated, results in the elimination of the effects of bad constituents of poor gasoline, such as the abnormal production of heat, as well as knocking, while at the same time the addition of such ingredients reduces the heating effect and raises the octane number. I In fact, .these effects may be controlled and the desired octane number may be produced even in the poorer grades of fuel.

It will be obvious to one skilled in the art that the proportions of aniline, butanol and ethyl alcohol that are used will be more or constituents of the less dependent upon the do not wish to be fuel used. I, therefore,

limited to any specific proportions thereof. 7

although the same should be substantially within the range of percentages above mentioned for best results.

What I claim as new and desire to. protect 4 by Letters Patent is In a motor fuel for internal combustion engines of the ex losive type comprising, an hydrocarbon suc as gasoline, the improvement which comprises the combination therewith of small percentages of aniline, butanol, and ethyl alcohol to prevent crystallization of the aniline at low temperatures and which combination prevents the separation of the ingredients in the presence of moisture condensed therein or otherwise introduced.

Signed this 30th day of January, 1931.

LEO B. KIMBALL. 

